1. Field of the Invention
The present invention relates to a data multiplexing network, a wavelength multiplexer and a data multiplexing transmission method, and more particularly to a data multiplexing network, a wavelength multiplexer and a data multiplexing transmission method for transmitting and receiving a plurality of packets through a single fiber.
All of patents, patent applications, patent publications, scientific articles and the like, which will hereinafter be cited or identified in the present application, will, hereby, be incorporated by references in their entirety in order to describe more fully the state of the art, to which the present invention pertains.
2. Description of the Related Art
In accordance with the state of the art for transmitting a plurality of packets over a communication network, data are entered into a plurality of ports of a data multiplexer and then subjected to a timing division multiplexing into a single wavelength data signal which is then transmitted through a single fiber. A communication service provider sets guarantee/non-guarantee classes or service classes in quality of service (QoS) for providing communication services through the communication network.
The service classes includes a band-guarantee service class which guarantees the quality of service in a predetermined limited wavelength band and a best effort service class which does not guarantee the quality of service. The communication service provider provides communication services to subscribers in accordance with the designated service class. A variety of improvements has been proposed for the packet transmission techniques in accordance with the designated service class.
Japanese laid-open patent publication No. 2001-197110 discloses one example of the conventional techniques for traffic control to guarantee the quality of service according to each service class. In accordance with this conventional traffic control method, a Differentiated Service (Diffserv) is made through an interface of a router which constitutes an IP network. In this Differentiated Service, PQ is made to the guarantee class service (EF class) for realizing a reduced delay and a reduced jitter, while WFQ (Weigfted fair queuing) is made to the best effort class service (AF class) to prevent any undesired influence to the guarantee class service (EF class), thereby to further improve fairness and band-utilization factor, resulting in realization of distributed priority services without band-guarantee. This realizes concurrently both services in accordance with the band-guarantee service class (EF class) and the best effort service class (AF class).
The above-described conventional traffic control method has the following disadvantages. An output from a device executing the traffic control such as a traffic controller or a router is a time-division-multiplexed signal, for which reason all of the IP packets are transmitted at a single wavelength.
All the packets to be transmitted are mapped in a single wavelength. This allows an undesired interference between respective service classes.
Further, the time-division-multiplexed signal with a single wavelength as outputted from the traffic controller is then transmitted through a single fiber. This means that increasing the band of the service classes needs increasing the number of fibers.
Japanese laid-open patent publication No. 10-164083 discloses another conventional technique of setting an end-to-end transmission path for data transmission through a network. This conventional method of setting the end-to-end transmission path is concerned with how to select any one of two networks with different service classes; for example, a guarantee network and a best effort network. This publication does not disclose nor teach any measures of transmission of plural packets through the single fiber in the data multiplex system.
In the above circumstances, the development of novel data multiplexing network, wavelength multiplexer and data multiplexing transmission method free from the above problems is desirable.